The present invention relates to lighting fixtures and luminaires, and more particularly to an improved optical assembly including a reflector/refractor device and a reflector collar for enhanced directional illumination control.
Various arrangements are known for reflectors when used as lighting fixtures and luminaires. Some known reflectors are manufactured in metals such as aluminum and steel, or of a glass or plastic. These materials are then painted, plated, or chemically brightened to function as reflectors. Vacuum metallizing, vapor or chemical deposition can be used to place a thin metal layer onto the surface of the metal, plastic or glass to act as reflector. There are also prismatic internal reflection glass and plastic reflectors which use the index of refraction to control the reflectance of light and redirect it into a distribution of light. Some glass reflectors are known to use a metal cover spun around the exterior to eliminate uplight, radiated by the large rounded portion of their prism peaks and roots, and the cover is used as a means of glare control and to maintain a clean exterior internal reflection surface. However, this creates a very dark reflector exterior and a very bright aperture brightness, and when installed in a room this reflector produces very reduced uplight with no means of adjusting the glass reflectors"" reflected surface brightness to any other ambient lighting concerns or conditions.
Improvements over prior art arrangements have been provided by prismatic reflector/refractor, such as disclosed in the following United States patents.
U.S. Pat. No. 4,839,781 issued to Josh T. Barnes and Ronald J. Sitzema Jun. 13, 1989 and assigned to the present assignee, discloses a reflector/refractor device for use with a variety of lighting fixtures and light sources. The reflector/refractor device includes a body having a predetermined profile and defining a cavity with the body having an inside surface and an outside surface. An illuminating source for emitting light is disposed within the cavity substantially along a central vertical axis of the body. The body includes a series of sectional zones for reflecting and refracting light. The exterior surface of the device includes a plurality of substantially vertical prisms consisting of reflective elements, refractive elements and elements that may be either reflective or refractive depending on light center location. These reflective or refractive elements act in combination to selectively vary light distribution characteristics of vertical and lateral angles, and intensities, by vertical displacement of the illuminating lamp source.
U.S. Pat. No. 5,444,606 issued to Josh T. Barnes and Paul C. Belding Aug. 22, 1995 and assigned to the present assignee, discloses a combination of a prismatic reflector and a prismatic lens is provided for use with lighting fixtures. A reflector body has a substantially parabolic contour defining an interior cavity. The reflector body includes a plurality of prisms for receiving, transmitting and reflecting light. A lens body has a first mating surface engaging the reflector body, an opposed inverted conical surface, and a sloping sidewall extending between the mating surface and the opposed inverted conical surface. The mating surface of the lens body has a larger diameter than the opposed inverted conical surface. The opposed inverted conical surface includes a plurality of prisms for receiving and for redirecting light.
Prior art of collar attachment to polymeric prismatic reflectors has been generally limited to using a stamped aluminum rings as a simple retention device, and generally as a means of reflecting extraneous light away from the Nadir position of a photometric distribution. These designs concentrated on producing batwing distributions.
The original reflector collar designs were intended to produce only batwing distributions with spacing criteria of 1.6:1 to 2.0:1. While the original designs of the collar and polymeric reflector provided excellent overall efficiency and coefficient of utilization for room cavity designs, it meant that batwing distributions would often need to be spaced closer than their intended spacing to meet required footcandle levels and watt per square foot energy consumption legislation. A need for narrower spacing with higher footcandle levels below the luminaire was needed to reduce the number of luminaires consuming energy in the lighted space. This also meant increasing or achieving horizontal footcandle requirements at the floor and maintaining vertical footcandle levels on shelving or racks of warehouses and interior lighting of commercial stores. In essence this is a shift in design practice which was to cover large areas of open space with uniform illumination, to a concept of concentrating illumination and energy use in narrower patterns for specific lighting requirements and tasks.
A need exists for effective mechanism for providing enhanced directional illumination control for an improved optical assembly. It is desirable to provide such an improved optical assembly for concentrating illumination and energy use in narrower patterns for specific lighting requirements and tasks.
A principal object of the present invention is to provide an improved optical assembly including a reflector/refractor device and a collar for enhanced directional illumination control. Other important objects of the present invention are to provide such an improved optical assembly including a reflector/refractor device and a collar for enhanced directional illumination control substantially without negative effect; and that overcome many of the disadvantages of prior art arrangements.
In brief, an improved optical assembly including a reflector/refractor device and a reflector collar provided for enhanced directional illumination control. The reflector/refractor has a predefined shape and has a plurality of reflector/refractor prisms on an exterior body surface for reflecting and refracting light. A light source is disposed within the reflector/refractor substantially along a central vertical axis of the reflector/refractor. The reflector collar supports the reflector/refractor and attaches the reflector/refractor to a luminaire ballast. The reflector collar has a predetermined contour and a plurality of reflector impressions formed into the predetermined contour. The predetermined contour and the plurality of reflector impressions provide directional illumination control for the optical assembly.